The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
High-power measuring instrument or medical device is susceptible to damage or malfunction due to a high-frequency noise due to an impulse applied to the input power. Therefore, high-power equipment is generally manufactured by way of inserting a filter between the apparatus and a power source to remove the high-frequency noise. A low-pass filter removes the high-frequency noise by using an inductor as a principal component. With the high power applied, the inductor typically needs to maintain a low resistance. However, inductors usually have high resistance and it is difficult to adjust their magnitude.
Therefore, a high-power rated variable inductor and a filter using it are in practical need.